Police engines

[Clem Clement]

I understand Henry put the B head on Model As and called then Police heads?
I understand for the eV-8's the police version did not come until 1953? I'm confused!
Clem

[Railcarmover]

In late 31 Ford made a 5.2 to 1 compression ratio model A head for police use,to identify it it has a large B cast into it,because of the B it gets confused with a model b production head,which is 4.6 to 1 and uses a 3 bolt V8 water pump.It became popular with the general public,The snyder 5.5 to 1 head is a copy of the chamber design,its called a 'heart chamber'.this snyder has been shaved.

[katy]

Ford made aluminum heads for the early V8s, whether they were higher compression ratio than the cast iron heads I do not know.
I was told they were for use in the mountains as they cooled better. True? I dunno.

[Benson]

I have been using Police heads (the head with the large B) since 1963 long before it was so easy to find these heads or buy repros.

I loved blowing past the "experts" at 60 MPH in their shiny perfect cars at 12,000 feet in mountains.

These were the same guys that picked apart every detail that was wrong with my Sport Coupe driver.

Fenders are body color ... top has wrong material, wheels are 19 inch... And on and on and on! ...

And heaven forbid ... "It has a hole in the hood where a fan blade went through it!!! "

[katy]

And heaven forbid ... "It has a hole in the hood where a fan blade went through it!!! "

It's called a battle scar, gives the car character.

[Railcarmover]

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I like'em both ways,stock and hopped up..aint much for the fancy paint.Ive got a 1936 model a 'service' head,a stock design A head casted in 1936,it seems a little stouter than a production head.


Ford script..and date coded..

[Terry, NJ]

I wish I knew what the HP increase is over the standard head. But that head (Pictured) would scare me. It appears to have entirely too much removed. I could be wrong, but! I believe in shaving heads, just not that much! It was 5.2 when it was new, it's probably close to 7.0 now. Let us know how it works out. By the way, the thickness of the head when new was 2.218 or 2 and 7/32 (1/32 under 2.250 or 2 and 1/4) I has always heard it was OK to take 1/8 (.125) off a Mod A head. I don't know if that applies to the "B" head or not. Good Luck!
Terry

[Purdy Swoft]

I've read that back in the day they would shave the head until the depth of the counter bore was only .030 thirty thousand . This was said to give the car more zip and power . This was probably before the police head was available . The shaved head still wouldn't have a compression ratio as high as the 5.2 B head . The B and C heads are concave on the valve side and if shaved too much it will lose clamping area on the valve side and this could cause a problem .

[Railcarmover]

Quench is the name of the measured distance between the head and piston at TDC.The engine I ran the shaved snyder on had zero piston protrusion,the distance the piston rises above the deck at TDC.Model a engines can have varying piston protrusion, I've seen .040..ford had a tolerance factor for protrusion,and over the year blocks have been decked.To use a zero piston relief head its important to factor quench to avoid the piston contacting the head.Quench is factored by taking the crushed head gasket thickness and subtracting protrusion..ideal model a quench is .040,which in my case I exceeded by .020 or so..or you can use plumbers putty and factor quench as well..but yeah Terry your right,you have to be on your game to run no piston relief.

[Clem Clement]

so who made the B heads and what were they used for?

[Terry, NJ]

As far as I know, Ford made them as an option for the police depts that were buying his cars. But why the "B" for an A, and the "C" head for the model B? Strange!
Terry

[Railcarmover]

And as a kicker there was no such thing as a C engine..

[40 Deluxe]

Originally Posted by Terry, NJ

As far as I know, Ford made them as an option for the police depts that were buying his cars. But why the "B" for an A, and the "C" head for the model B? Strange!
Terry

To distinguish the higher compression "police head" from the regular head, Ford cast a 'B' on the head. When the 'B' engine came out, since Ford was already using 'B' for the Police Head, they used 'C' on the head because it was different from the previous heads (3 bolt water pump, mainly).

[Clem Clement]

that is how I understand it, but why did Henry not offer police options on his eV-8s until 1950?

[Terry, NJ]

This raises some questions . Such as why not A-1 for the A police heads, Also, B for B heads. And the best question of all, what about a police head for the mod Bs. I understand the V8s were the police cars, but a mod B, high compression "police" head would have made a nice option.
Terry

Originally Posted by 40 Deluxe

To distinguish the higher compression "police head" from the regular head, Ford cast a 'B' on the head. When the 'B' engine came out, since Ford was already using 'B' for the Police Head, they used 'C' on the head because it was different from the previous heads (3 bolt water pump, mainly).

[Bob Bidonde]

I found these dyno test results on the internet. Judging by the numbers, they are at the flywheel:
4.2:1 Head: 38 HP & 130 lbs-ft Torque;
5.5:1 Head: 47 HP & 141 lbs-ft Torque;
6:1 Head: 58 HP & 146 lbs-ft Torque.

[Railcarmover]

There lies the demise of the model a Terry..it didn't develop enough power to compete in the market.Police departments then,as now require speed and power.Ford spent 5 years developing the X8 engine,when it proved to be a failure Mr Ford was urged to use a 6 cylinder engine for the A,he refused,stating he wasn't joining the market,he led the market..so the 4 cylinder engine design was used,rendering the car obsolete in a few years.

The model a chassis design had a 20 year run however and the V8 engine had a 21 year run. A difficult and flawed and engine it was,the casting rejection rate for V8 blocks was 90 percent...any other company would have walked away from it,it took till 1936 before the design evolved well enough.And that brings up the model T,Ford made so much money with the T it carried the company when it didn't turn a profit from '29 to '46 ( war work was done at cost plus one dollar).Ford could afford to live with the V8..

[Railcarmover]

Originally Posted by Bob Bidonde

I found these dyno test results on the internet. Judging by the numbers, they are at the flywheel:
4.2:1 Head: 38 HP & 130 lbs-ft Torque;
5.5:1 Head: 47 HP & 141 lbs-ft Torque;
6:1 Head: 58 HP & 146 lbs-ft Torque.

Compression helps greatly,so does fuel..one caveat with high compression heads,the effect of detonation or spark knock is severe,the lower compression engine tolerates it better. Detonation issues with high compression heads and model a distributors are common.The mechanical advance distributor (model B) solves the issue.Its why Ford introduced it in '32 as part of the 'new and improved' 4 cylinder engine.

[Mikeinnj]

Originally Posted by Railcarmover

Compression helps greatly,so does fuel..one caveat with high compression heads,the effect of detonation or spark knock is severe,the lower compression engine tolerates it better. Detonation issues with high compression heads and model a distributors are common.The mechanical advance distributor (model B) solves the issue.Its why Ford introduced it in '32 as part of the 'new and improved' 4 cylinder engine.

Can a mechanical advance distributor be fitted to a Model A engine and what other physical changes are required, such as the timing cover.?

[Charlie Stephens]

Originally Posted by Mikeinnj

Can a mechanical advance distributor be fitted to a Model A engine and what other physical changes are required, such as the timing cover.?

The Model B distributer will go into the Model A engine but the Model B timing cover must also be used if you are going to time it by the book using the pin. Check the archives for work around timing methods. You will also need to modify the wiring and ignition switch since the Model B distributer does not have an armored cable going to it. Security for the Model B vehicle was provided by a locking steering column.

Charlie Stephens